Needle sharpening apparatus



July 10, 1962 G. A. BELL ETAL 3,043,060

3,043,060 NEEDLE SENING APPARATUS George Anketell Bell, West Pymble, NewSouth Wales,

and James Lobb, Caringbah, New South Wales,

Australia, assignors to Commonwealth Scientific and Industrial ResearchOrganization, East Melbourne,

Victoria, Australia, a body corporate of Australia Filed Oct. 28, 1959,Ser. No. 849,369 Claims priority, application Australia Oct. 30, 1958 18Claims. (Cl. 51-122) This invention relates to apparatus for sharpeningor resharpening hypodermic needles and similar hollow needles which willbe referred to collectively hereinafter as needles.

Such a needle has a point formed on it primarily by producing on one enda flat or curved bevel surface oblique to the needle axis.

The present invention relates to the surfacing or resurfacing of flat orconcave bevels.

The object of sharpening a hypodermic needle is to produce a sharpdurable point on the end of the needle flanked by two sharp edges sothat when the point of the needle penetrates the epidermis the edgeswill cut the skin and underlying tissue and permit the entry of thecannula without tearing of the tissue.

A sharp edge is formed by the intersection at an appropriate angle oftwo smooth surfaces. If the surfaces are flat, the edge. formed by theirintersection will be straight and if the surfaces are smooth the edgeformed by their intersection will be free from serrations and similarimperfections. The point may be formed by the intersection at anappropriate angle of three or more' smooth surfaces. The point will besharp and free from burrs if the intersections and surfaces forming itare smooth.

A sharp point may also be formed by the intersection of a plane with aconvex cylindrical surface.

A needle of one or all of these types may be sharpened or resharpened byproducing on it a new bevel surface which is very smooth all over and isfree from burrs, turned edges or crumbled edges.

It is desirable also that any method of resharpening needles shouldreproduce accurately the form and angle of the original bevel angle ifthis is the optimum or that the bevel angle shall be adjustable at will.

A finish of this type is conveniently achieved by lapping the surface ona suitable metal lap in which is embedded abrasive powder of a suitablehardness and particle size.

The object of the present invention is to provide apparatus forsharpening or resharpening flat bevels more satisfactorily than is thecase with existing apparatus for the purpose.

Another object of this invention is to provide apparatus for thesharpening of needles which incorporates all of the above desirablefeatures.

In a general form the invention is needle sharpening apparatus includinga rotatable lap having a working surface, a block supported on the saidlap surface at spaced locations and spaced from the surface between saidlocations and having an associated abutment edge substantially parallelto a generator of the said surface of the lap and spaced from the saidsurface, the lap and abutment edge being adapted to receive between thema needle end to be bevelled and sharpened with the needle end bevelsurface contacting the said lap surface and the needle outer surfaceadjacent to the end to be sharpened contacting the abutment edge, andmeans for guiding the needle, the disposition of the guide means inrelation to the lap being such that the bevel produced on the needle3,043,060 Patented July '10, 1962 ice end by contact between the needleend and the rotating lap surface has substantially the required anglewith the needle axis.

Means are provided for moving the engaging surfaces of the needle beveland lap relatively so as to abrade the bevel surface.

A preferred form of the invention is shown in the accompanying drawing.

A lap disc 10 is located within and spaced from a shallow cylindricalwall 11. Conventional means (not shown) are provided for rotating thedisc 10 about its centre. spaced from the disc 10 and supported at itsends on posts 12A. On the bar is slidably mounted a block carrier 13with an extension 14 from which a block 15 is suspended by screws 16.The block is biased away from the carrier and against the disc 10 bysprings 17 surrounding the respective screws 16. The block is supportedon the disc by tungsten carbide underflats 18, one at each end, the partof the block between the underfiats being spaced from the disc 10.

A bar 19 is adjustably secured to the face 20' of the block, betweenparallel wings 21 extending from the block, by screws 22 extending intothe block through slots 23 in the bar 19. A comb plate 24 with spacedslots 25 is secured to and between the wing outer ends. Elongated holesmay be substituted for the slots 25. The carrier 13 is reciprocated onthe bar 12 by means of a connecting rod 26 pivoted at one end 27 to thecarrier and at the other end 28, off-centre, to a disc 29 secured on theupper end of a rotatable shaft which may pass through a hole in the bar12.

The objects of the reciprocation of the carrier 13 and with it the block15 is to distribute Wear as much as possible.

The components so far described are supported on a table or platform 30at an angle to the vertical approximately equal to the angle between therequired bevel plane and the needle axis. The needles 31 to be sharpenedare disposed vertically in the respective comb slots 25 with the bevelplane to be lapped engaging the disc and the outside of the needle nearits point against the abutment edge 32 of the bar 19. The edge 32 isparallel to the disc surface.

A pressing plate 33 is secured to an arm 34 passing at its outer endbetween posts 35.

An extension 36 of therotatable shaft carrying the disc 10 is locatedoff-centre in and secured to a disc 37;

falls into the space between the disc 10 and the wall 11- and is removedthrough a pipe 41.

The function of the plate 33 is to distribute abrasive powder over thedisc surface and to press it into the disc. The purpose of the groovesis to remove debris from the surface of the disc and to remove burrsfrom the edges of the needle bevel.

In a further form of the invention, for producing cylin drical insteadof flat bevel surfaces, a cylindrical lap disposed with its axishorizontal is employed.

As before a block is provided with an abutment edge spaced from andsubstantially parallel to a generator of the cylindrical lap surface.Each needle is disposed and A guide bar 12 extends across parallel toand guided vertically, point downwards, with its pointed end between thelap and the abutment edge, the bevel engaging the lap surface and theopposite outer surface engaging the abutment edge.

Where it is required to sharpen or resharpen'needles, some with flatbevels and others with cylindrical bevels, a composite lap' may beemployed having both a cylindrical lap surface and a flat circular endlap surface. Either lap surface may then be used according to the bevelrequired. For both fiat and cylindrical laps rotation may be in eitherdirection.

What we claim is:

1. Apparatus for sharpening a needle comprising a rotable lap, having aworking surface, a block contacting said working surface at spacedlocations, the block being spaced from said working surface between saidlocations, said block having an abutment edge substantially parallel tosaid working surface and spaced therefrom,.said working surface andabutment edge defining a support for said needle, the needle having asurface adaptedfor contacting the working surface so that the surface ofthe needle is beveled at a determinable angle, the needle having anouter surface adjacent the first said surface thereof and adapted tocontact the abutment edge, andspaced guides above the abutment edge,each guide adapted for supporting said needle and cooperating with theabutment edge and the working surface of the lap to maintain the needlein a substantially upright position, the surface of the, lap which isadjacentlto the first said needle surface being inclined with respect tothe vertical at an angle substantially equal to the angle of the beveledsurface of the needle.

2. Apparatus as in claim 1, including also means for feeding abrasivematerial onto the lap surface.

3. Apparatus as in claim 1, wherein the lap surface has grooves formedin it.

4. Apparatus as in claim 1, including means for biasing the blocktowards the lap surface.

5. Apparatus as in claim 1, including means for reciprocating the blockover the lap surface.

6. Apparatus as in claim 1, wherein the lap is a disc.

7. App ratus as in claim 6, wherein the grooves are approximatelyradial.

8. Apparatus as in claim 1, wherein the lap is a disc, and comprising aguide bar extending across and spaced from the lap surface, a blockcarrier mounted on the 7 guide bar, the block being attached to theblock carrier and spaced from the lap surface for at least part of itslength, spaced underflats on said carrier and supported on the lapsurface, the abutment edge of the block being spaced from the lapsurface.

9. Apparatus as in claim 8, including means for urging the blockunderflats against the lap surface.

10. Apparatus as in claim 8, wherein the block carrier is slidablymounted on the guide bar and comprising means for reciprocating thecarrier along the guide bar.

11. Apparatus as in claim-8, including means for feeding abrasivematerial onto the lap surface.

12. Apparatus as in claim 11, wherein the lap surface has grooves formedin it.

13. Apparatus as in claim 12, wherein the grooves are approximatelyradial.

14. Apparatus as in claim 11, including pressing means for pressing intothe lap surface abrasive material fed thereon. J

15. Apparatus as in claim 14, wherein the pressing means comprises apressing plate pressing against the lap surface.

16. Apparatus as in claim 15, including means for reciprocating thepressing plate over the lap surface.

17. Apparatus as in claim 8, comprising spaced wings extending from theblock adjacent to the respective ends of the abutment edge, the needleguiding means comprising a comb plate secured to the outer ends of thewings and extending therebetween, the comb plate havin}; spaced slots,each adapted to support and guide said needle.

18. Apparatus as in claim 1, the abutment edge being on an abutment baradjustably secured to the block.

References Cited in the file of this patent UNITED STATES PATENTS670,593 Murnane Mar. 26, 1901 2,180,952 Gattoni Nov. 21, 1939 2,368,108-Bourgeois 19.11.30, 1945 2,404,282 Fruth July 16, 1946 2,663,976 'JacobyDec. 29, 1953 2,797,534 Rouse July 2, 1957 2,821,051 Franz Jan. 28, 1958v FOREIGN PATENTS 9,233 Great Britain May 2, 1905

